Fleet maintenance agreements, leasing agreements and/or certain governmental regulations require the use of a device to accurately record the distance traveled by a commercial vehicle. One device, commonly known as a hubodometer, is typically bolted or otherwise attached to a wheel hub of the vehicle where it senses rotation of the wheel, the sensed rotation being correlated with distance traveled. In that this distance information is used for determining highway usage fees as well as for compliance with contractual agreements, it is imperative that the recording device be manufactured in a manner which prevents intentional or inadvertent alteration of the distance information. It is also imperative that the recording device be immune to transient movements of the device such that such movements are not interpreted as a rotation of the wheel hub.
This problem has been solved by using a weighted mechanical assembly that sits on the end of the axle of the trailer. As the wheel turns, the weighted assembly stays stationary. This provides a relative motion that can drive a geared odometer. The problems with this method are that vibration can induce spin into the weighted assembly which makes the unit stop counting since there is no longer any relative motion with respect to the wheel to turn the internal gears. This forces the unit to inherently undercount overtime. Another limitation to this method is that every wheel needs different parts and gears so that mileage is displayed correctly on different wheel sizes. Not all wheel sizes can be supported in this manner though. A further limitation relates to the effect of wheel impacts when driving over rough surfaces or rocks. These impacts can impart inaccuracies into the odometer count.
In the past solutions have been proposed including an electronic solution to the gearing problems. This is shown in FIG. 1. The gearing on the weighted assembly 24 is replaced with a magnet 10 mounted on the rotating portion and one or more magnetic switches 12 mounted on the weighted assembly 24. As the wheel 5 rotates in a counter clockwise direction as indicated by the arrow 25, over a surface 30, the magnetic switch 12 closes to provide an electrical impulse to the counter 18 when the magnet 10, rotating with the wheel 5, rotates past the switch 12.
This configuration solves the problems of gear ratios since software defines the counts per mile now; however, the unit still has essentially all the same mechanical components to keep the weighted assembly from spinning. This leads to more cost on a unit that still has the same failure modes plus a few new ones such as rocking and battery life problems. There still exists the problem of road impacts 40 disturbing the counting mechanism 18.
It would therefore be beneficial to have an electronic hubodometer with no moving internal parts, capable of accurately tracking mileage while minimizing distortions due to wheel impacts and vibrations.
It would be further beneficial to monitor hubodometer data from a location remote from the wheel. Preferable locations would include inside the passenger compartment of the vehicle; from a hand held monitor; or from a building proximate to where the vehicle is stored. When working with a fleet of vehicles, it would further be beneficial to provide hubodometer information on a network where it is accessible from a plurality of locations. These include the Internet and cellular or satellite monitoring systems.